Three-phase clarifier



Oct. 3, 1967 D. B. TODD THREE-PHASE CLARIFIER Filed Feb. 8, 1965 '2 Sheets-Sheet 1 WUELEDQQE PIMZJ INVENTOR; DAVID B. TODD BY EM W, m, f gmuga VATT'YS Oct. 3, 1967 D. B. TODD THREE-PHASE CLARIFIER 2 Sheets-Sheet 2 Filed Feb. 8, 1965 oufzmaju .So mwEEEE mz P36 mufzznas: P10:

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United States Patent 3,344,982 THREE-PHASE CLARIFIER David B. Todd, Park Ridge, 111., assignor to Dresser Industries, Inc., Dallas, Tex., a corporation of Texas Filed Feb. 8, 1965, Ser. No. 430,925 8 Claims. (Cl. 233-15) ABSTRACT OF THE DISCLOSURE A centrifugal separator for sequential separation of heavy and light impurities from a feed liquid includes a rotor casing of cylindrical configuration defined by a shaft, parallel end walls and an intermediate partition fixed to the shaft, and a closing peripheral Wall, defining two sideby-side chambers. The rotor is hermetically sealed, and each of the chambers is provided with radially spaced bands having perforations permitting radial flow through the bands. The feed liquid is fed to the first working chamber, and centrifugal separation occurs followed by removal of either the heavy phase or the light phase from either the outer extremity or the inner extremity of the first chambr respectively. The partition is provided with bypass ports whereby the nonremoved phase is passed to the second working chamber for additional clarification by the centrifugal action. The heavy and light phases are removed from the second chamber by ports provided at the radially outer and inner extremities of the second working chamber respectively.

essing has been required, involving the use of two different apparatuses. Consequently, if sufiicient capacity can be provided by a single unit, as is frequently the case, necessity of a second unit may double the apparatus cost. What has been needed is a single centrifugal apparatus which is capable of removing both heavy and light phase materials from a liquid of intermediate density while operating at high capacity and under completely hermetic conditions. i

It is, therefore, an object of this invention to provide a single centrifugal apparatus of the hermetic type which is capable of functioning as a three-phase splitter, thereby making it possible to separate both heavy phase material and light phase material from a feed stock or other liquid of intermediate density. Further objects and advantages will be indicated in the following detailed specification. This invention is shown in illustrative embodiments in the accompanying drawings, in which:

FIGURE 1 is a front elevational view of a centrifugal apparatus embodying design features of the present invention;

FIGURE 2 is a side sectional view taken on line 22 FIGURE 3 is a front elevational view of a modification of the apparatus of FIG. 1; and

FIGURE 4 is a side sectional view taken on line 4-4 of FIG. 3.

The apparatus of FIGURE 1 may be taken as illustrative of the general features of all of the apparatuses described herein. As shown in FIG. 1, the apparatus includes a rotor casing 10 which is mounted coaxially on a shaft 11 and provides a radially-extending working space therein. The casing 10 is of cylindrical configuration, being formed of a cylindrical outer band 10a, and end plates 10!; and 100. The end plates 1% and are suitably atfixed by welding or bolting to the outer ends of band 10a and to the shaft 11, which, in the illustration given, extends through the inner portion of the rotor working space. It will be understood that this provides a hermetically sealed casing around the working space which permits the working space to be maintained at superatmospheric pressure.

Shaft 11 extends horizontally and is rotatively mounted on a base 12 by means of suitable bearings 13a, 13b. The outer enclosure or shell 14 extends around the upper portion of rotor 10, and is adapted for ready removal to permit access to the rotor.

As is well known in the art, means is provided for driving shaft 11 at controlled rotational speeds, such as the driven sheave 15. Conduits are connected to stationary shaft extensions 15 and 16 for the introduction and removal of liquids through passages in the shaft. In the illustration given, the left-hand portion of shaft 11 and the corresponding shaft extension 15 are provided with central passage 17, and with a surrounding annular passage 18. In the operational set-up of FIGURE 1, central passage 17 is employed for supplying the feed stock to be treated, that is, the feed stock of intermediate density containing both heavy phase material and light phase material which is to be removed therefrom. As will subsequently be explained in greater detail, passage 18 is employed for removal of the heavy phase material. The inner end of passage 17 connects with branch passages in the shaft which in turn connect to inlet tubes 19 and 20. The inner end of passage 18 connects with lateral passages in the shaft which communicate with the space 21 between end plate 10]; and a disc 22.

Similarly, the right-hand portion of shaft 11 and the corresponding shaft extension 16 are provided with a central passage 23, and a surounding annular passage 24. Central passage 23 communicates with branch passages 23a in the shaft which extend to the inner portion of the rotor to provide for the removal of light phase material. The inner end of passage 24 through branch passages in the shaft communicates with the space 25 provided between end plate 10c and disc 26. Passage 24 is employed for the removal of the clarified feed.

In accordance with the present invention, rotor 10 is provided internally with a partition means 27 which extends through and divides the rotor working space, the partition, as shown, preferably extending outwardly between shaft 11 and the outer portion of the rotor casing, which, in the embodiment shown, is the cylindrical band 10a. Partition means 27 divides the working space into two side-by-side working chambers 28 and 29. In the illustration given, chamber 28 has a greater axial extent, and therefore a larger volumetric capacity, than chamber 29. However, in other embodiments, partition 27 may be located to provide side-by-side chambers of equal size, or so chamber 29 is larger than chamber 28. The inner end of partition 27 is rigidly connected and sealed to shaft 11 by some suitable means such as welding, as is the outer end of the partition to casing band 10a.

For convenience of reference, the left-hand chamber 28 may be designated as the first working chamber, while the right-hand chamber 29 may be designated as the second working chamber. It will be understood, of course, that these chambers and the respective operational arrangements and functions may be reversed. In accordance with the present invention, the first working chamber, such as the chamber 28, is provided with inlet means for supplying the feed stock. In the illustration given, the inlet means comprises the tubular inlet conduits 19 and 20, which communicate with shaft passage 17, and terminate at a radially intermediate protion of chamber 28.

The first chamber 28 is also provided with outlet means extending between the first chamber and a second of the shaft passages for removing one of the heavy phase or light phase materials from the chamber after separation from the feed stock. In the embodiment of FIGURE 1, an outlet means is provided for removing heavy phase material. For this purpose, a spill-over disc arrangement may be used, the upper end of the disc 22 being spaced inwardly from casing band a to provide an annular opening 30 which communicates with space 21, and in turn with shaft passage 18. As will be noted, the heavy phase outlet means communicates with the outer portion of chamber 28.

For transferring the partially clarified feed from the first chamber 28 to the second chamber 29, partition 27 is provided with by-pass opening means 31. In the embodiment of FIGURE 1, the by-pass means 31 is provided adjacent shaft 17, and provides communication between the inner portions of the chambers 28 and 29. The feed stock, after separation of the heavy phase material in chamber 28, passes through by-pass 31 to the inner portion of chamber 29. Preferably, a plurality of the openings 31 are provided. For example, the openings may be in the form of slots, as shown more clearly in FIGURE 2.

Chamber 29 is provided with two kinds of outlet means extending respectively from the inner and outer portions of the chamber to different shaft passages. In the embodiment shown, lateral passages 23a extend from the inner portion of chamber 29 to shaft passage 23 for the removal of the light phase material.

To provide for removal of the fully clarified feed from the outer portion of chamber 29, disc 26 terminates inwardly of casing band 10a to provide an annular opening 32 which communicates with space 25. As previously explained, space 25 connects to shaft passage 24 through which the clarified feed can be removed from the apparatus. As is well known in the art, other means can be provided for the introduction and removal of the phases from chambers 28 and 29.

'Each of the working chambers 28 and 29 are preferably provided with a plurality of clarifying elements to promote separation and coalescence of the phases. For example, as shown, the chambers may be provided with a plurality of radially-spaced perforated rings. The rings are supported in suitable grooves. In the embodiment shown, the rings 33 are supported in grooves in disc 22 and partition 27, while the rings 34 are supported in grooves in the partition 27 and the disc 26. Where outlets are provided without using spill-over discs, the outer ends of the rings can be supported in grooves in end plates 10b and 100. Instead of perforated rings, other clarifying elements can be used, such as axially-spaced, radially-extending discs, as described in Patent 3,053,440. Also, a combination of rings and discs may be used. Such elements arrest rotational swirl, and thereby promote clarification and separation.

In the embodiment of FIGURE 1, four shaft passages are provided, and this requires four dynamic seals to permit the liquids to be transferred from rotating shaft 11 to the stationary shaft extensions and 16. In this embodiment, seals 35 and 36 are provided between shaft extension 15 and shaft 11, while seals 37 and 38 are provided between shaft 11 and shaft extension 16. Since the construction of such seals is well known in the art, it is not believed that it will be necessary to further describe them herein. As will be noted, seals 35, 36, 37, and 38 cooperate, respectively, with shaft passages 17, 18, 24, and 23.

Turning now to FIGURE 3, there is shown a modification of the apparatus of FIG. 1 which may be employed where it is first desired to separate the light phase material, and thereafter the heavy phase material. The corresponding parts have been given the same numbers, except that the numbers have been primed to indicate that they are applied to a modified construction.

In the embodiment of FIGURE 3, first chamber 28' is provided with a light phase outlet means which communicates with the inner portion of the chamber for removing the light phase material. In the illustration given, this consists of lateral passages 18' which extend from the inner portion of the chamber 28' to shaft passages 18. The feed stock to be processed is still supplied through the inlet tubes 19 and 20' from shaft passage 17'.

The construction of partition means 27' is modified so that the by-pass opening means 31 is adjacent casing ring 10a, and provides communication between the outer portions of chambers 28' and 29'. As shown more clearly in FIGURE 4, the opening means 31' may consist of a plurality of circumferentially-spaced slots. It will also be noted that partition 27' is located approximately equidistantbetween end plates 10b and thereby making the chambers 28' and 29 of approximately equal size and volume.

For the construction shown in FIGURE 3, the partially clarified feed stock (after removal of the light phase material) passes through the openings 31' in the outer portion of chamber 28 to the outer portion of chamber 29'. The feed stock then flows inwardly, and is ultimately removed from the inner portion of chamber 29' through shaft passages 23a which communicate with shaft passage 23'. The heavy phase material is removed from the outer portion of chamber 29' through annular opening 32' which communicates with space 25' between end plate 10c and disc 26'. Shaft passage 24', through lateral connecting passages, communicates with space 25'.

It will be readily seen that FIGURES 1 and 3 comprise two embodiments of the same inventive design c0nception. For some applications, the arrangement of FIG. 1 may be preferable, while in others the arrangement of FIG. 3 will give better results. This will depend uponthe particular systems being processed, the relative volumes of the heavy phase material, the light phase material, and the intermediate feed stock phase. With either embodiment, the outlet means for removing the heavy or light phase material from the first chamber 28 is preferably located outside of the intermediate portion of the chamber. As previously described, the outlet means may be located in the outer portion of the first chamber when the heavy phase material is to be removed thereby, and in the inner portion of the first chamber when the light phase material is to be removed thereby. It will be understood, of course, that the first chamber will contain one of the outlet means, that is, a heavy phase outlet means in the outer portion of the chamber, or a light phase outlet means in the inner portion of the chamber, but not both.

It will also be understood that with either the embodiment of FIGURE 1 or FIGURE 3, the bypass means 31 or 31' should be located in a position radially remote from the position of the first chamber outlet means (e.g., 30, 18'). For example, by-pass means 31, 31 may provide communication between either the inner portions of the chambers or the outer portions of the chambers. Where the first chamber contains heavy phase outlet means, the by-pass means will be located at the inner portion of the chamber, while if the first chamber provides a light phase outlet means, the by-pass means will be located in the outer portion of the chamber.

It will also be apparent that the second chamber 29 or 29' will contain one kind of outlet means extending between the chamber and a third one of the shaft passages for removing the other of the materials from the feed stock than the material removed in chamber 28 or 28. Chambers 29 or 29 will also be provided with another kind of outlet means extending between the chamber and a fourth one of the shaft passages for removing the feed stock after separation of the other material. The two kinds of outlet means will be located respectively in the inner and outer portions of the second chamber, but the inner and outer portions of the second chamber will each contain only one of the two kinds of outlet means.

The operation of the apparatus of this invention will be readily aparent from the foregoing discussion to those familiar with the operation of similar equipment. The feed will be supplied under pressure such as by means of a pump, and throttle valves may be provided on each of the outlet lines to control back pressure, thereby regulating the position of the principal interface within the hermetic chambers which are maintained under superatmospheric pressure. To illustrate the flow of the phases, arrows have been aplied to FIGURES 1 and 3, and legends are also used to identify the liquids introduced and removed from the shaft passages. As there shown, the apparatus is particularly adapted for the separate removal of light and heavy impurities from a feed stock of intermediate density, thereby producing a clarified feed substantially free of both light and heavy impurities. For example, water contaminated with both heavy and light oil, that is, with oil having a density greater than that of water, as well as with oil having a density less than that of water, can be processed to obtain substantially oil-free water. Similarly, water containing carbonaceous sludge which has a density greater than water, and also light oil having a density less that water, can be processed to remove both the sludge and the oil, thereby obtaining clarified water substantially free of both sludge and oil.

The apparatus of this invention may also be employed for the separation of a three-phase mixture into its constituent parts where the light or heavy phase is the feed stock or desired product, while at the same time it is desired to separate the phase of intermediate density from the other phase. For example, in the separation of the mixture produced by sulfuric acid acidulation of soap stock obtained from caustic refining of undegummed soybean oil, three phases are formed. The light phase consists of acidulated grease (free fatty acids in neutral oil). The heavy phase is the aqueous solution of the sodium sulfate by-product (as Well as other miscellaneous impurities). The intermediate phase is primarily an emulsion of fatty acids, lecithin, and Water. By removing the intermediate phase separately, it may be processed further without contaminating either of the two named product streams. A similar application may also be made in soap manufacturing wherein the nigre phase is separated.

While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that many of the detail described herein can be varied considerably without departing from the basic principles of the invention.

I claim:

1. In a centrifugal apparatus for separation of a threephase liquid mixture into its constituent parts, the combination comprising a rotatively mounted shaft providing a plurality of liquid flow passages therein, a rotor casing mounted coaxially on said shaft and providing a hermetically-sealed, pressure-retaining working space therein extending outwardly from said shaft, partition means mounted within said rotor casing to extend outwardly between said shaft and the outer portion of said casing, said partition means dividing said working space into two sideby-side chambers, inlet means for supplying the said threephase mixture to a first one of said chambers from a first one of said shaft passages, outlet means extending between said first chamber and a second of said shaft passages for removing one of said phases after separation from said mixture, by-pass opening means provided in said partition means for transferring the remaining mixture to said second chamber after said one phase has been separated in said first chamber, said by-pass means being located in a position radially remote from the position of said first chamber outlet means, one kind of outlet means extending between said second chamber and a third one of said shaft passages for removing a second one of said phases, and another kind of outlet means extending between said second chamber and a fourth one of said shaft passages for the remaining one of said phases, said one kind of outlet means and said other kind of outlet means being located in the inner and outer portions of said second chamber, With said inner and outer portions of said second chamber each containing only one of said two kinds of outlet means.

2. The combination of claim 1 wherein said first chamber outlet means communicates with the outer portion of said chamber for removing heavy phase material, said by-pass opening means extends between the inner portions of said first and second chambers, said one kind of outlet means communicating with the inner portion of said second chamber for removing said light phase material, and said other kind of outlet means communicating with the outer portion of said second chamber.

3. The combination of claim 1 wherein said first chamber out-let means communicates with the inner portion of said first chamber for removing said light phase material, said by-pass opening means extends between the outer portions of said first and second chambers, said one kind of outlet means communicates with the outer portion of said second chamber for removing said heavy phase material, and said other kind of outlet means communicates with the inner portion of said second chamber.

4. The combination of claim 1 wherein each of said chambers is provided with a plurality of clarifying elements to promote separation of said phases.

5. In a centrifugal apparatus for sequential separation of heavy phase material and light phase material in admixture with a liquid of intermediate density with respect to said heavy and light phase materials, the combination comprising a rotatively mounted shaft providing a plurality of liquid flow passages therein, a rotor casing mounted coaxially on said shaft and providing a hermetically-sealed, pressure-retaining working space therein extending outwardly from said shaft, partition means mounted within said rotor casing to extend outwardly between said shaft and the outer portion of said casing, said partition means dividing said working space into two side-by-side chambers, inlet means for supplying said mixture to the intermediate portion of a first one of said chambers from a first one of said shaft passages, outlet means extending between said first chamber and a second of said shaft passages for removing one of said materials after separation from said mixture, said outlet means being located outside of the intermediate portion of said chamber, said outlet means being in the outer portion of said first chamber when said heavy phase material is to be removed thereby, and in the inner portion of said chamber when said light phase material is to be removed thereby, but said first chamber containing said outlet means in only one of said locations, by-pass opening means provided in said partition means for transferring the remaining mixture to said second chamber after said one material has been separated in said first chamber, said by-pass means being located in a position radially remote from the position of said first chamber outlet means, one kind of outlet means extending between said second chamber and a third one of said shaft passages for removing the other of said materials from said liquid of intermediate density, and another kind of outlet means extending between said second chamber and a fourth one of said shaft passages for removing said liquid after separation from said other of said materials, said one kind of outlet means and said other kind of outlet means being located in the inner and outer portions of said second chamber, with said inner and outer portions of said second chamber each containing only one of said two kinds of outlet means.

6. The combination of claim 5 wherein said first chamber outlet means communicates with the outer portion of said chamber for removing heavy phase material, said bypass opening means extends between the inner portions of said first and second chambers, said one kind of outlet means communicating with the inner portion of said second chamber for removing said light phase material, and said other kind of outlet means communicating with the outer portion of said second chamber.

7. The combination of claim 5 wherein said first chamber outlet means communicates with the inner portion of said first chamber for removing said light phase material, said by-pass opening means extends between the outer portions of said first and second chambers, said one kind References Cited UNITED STATES PATENTS 6/1947 Bramley 233l8 X 9/1958 Fear et al. 23315 X M. CARY NELSON, Primary Examiner.

of outlet means communicates with the outer portion of 15 HENRY T. KLINKSIEK, Examiner. 

1. IN A CENTRIFUGAL APPARATUS FOR SEPARATION OF A THREEPHASE LIQUID MIXTURE INTO ITS CONSTITUENT PARTS, THE COMBINATION COMPRISING A ROTATIVELY MOUNTED SHAFT PROVIDING A PLURALITY OF LIQUID FLOW PASSAGES THEREIN, A ROTOR CASING MOUNTED COAXIALLY ON SAID SHAFT AND PROVIDING A HERMETICALLY-SEALED, PRESSURE-RETAINING WORKING SPACE THEREIN EXTENDING OUTWARDLY FROM SAID SHAFT, PARTITION MEANS MOUNTED WITHIN SAID ROTOR CASING TO EXTEND OUTWARDLY BETWEEN SAID SHAFT AND THE OUTER PORTION OF SAID CASING, SAID PARTITION MEANS DIVIDING SAID WORKING SPACE INTO TWO SIDEBY-SIDE CHAMBERS, INLET MEANS FOR SUPPLYING THE SAID THREEPHASE MIXTURE TO A FIRST ONE OF SAID CHAMBERS FROM A FIRST ONE OF SAID SHAFT PASSAGES, OUTLET MEANS EXTENDING BETWEEN SAID FIRST CHAMBER AND A SECOND OF SAID SHAFT PASSAGES FOR REMOVING ONE OF SAID PHASES AFTER SEPARATION FROM SAID MIXTURE, BY-PASS OPENING MEANS PROVIDED IN SAID PARTITION MEANS FOR TRANSFERRING THE REMAINING MIXTURE TO SAID SECOND CHAMBER AFTER SAID ONE PHASE HAS BEEN SEPARATED IN SAID FIRST CHAMBER, SAID BY-PASS MEANS BEING LOCATED IN A POSITION RADIALLY REMOTE FROM THE POSITION OF SAID FIRST CHAMBER OUTLET MEANS, ONE KIND OF OUTLET MEANS EXTENDING BETWEEN SAID SECOND CHAMBER AND A THIRD ONE OF SAID SHAFT PASSAGES FOR REMOVING A SECOND ONE OF SAID PHASES, AND ANOTHER KIND OF OUTLET MEANS EXTENDING BETWEEN SAID SECOND CHAMBER AND A FOURTH ONE OF SAID SHAFT PASSAGES FOR THE REMAINING ONE OF SAID PHASES, SAID ONE KIND OF OUTLET MEANS AND SAID OTHER KIND OF OUTLET MEANS BEING LOCATED IN THE INNER AND OUTER PORTIONS OF SAID SECOND CHAMBER, WITH SAID INNER AND OUTER PORTIONS OF SAID SECOND CHAMBER EACH CONTAINING ONLY ONE OF SAID TWO KINDS OF OUTLET MEANS. 